Arrow shaft and method for manufacturing the same

ABSTRACT

An arrow shaft composed of a non-elastic fiber and a low elastic fiber and a method for manufacturing the same are disclosed. The method comprises the steps of spreading an elastic sheet such as pre-impregnated or prepreged carbon or glass fiber, adhering a non-elastic or low elastic fiber, preferably a prepreged pre-impregnated natural, synthetic, or glass fiber onto the elastic sheet, winding them onto a mandrel, and carrying out tapping, heat treating/cooling, releasing, and polishing processes.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for manufacturing anarchery arrow, and more particularly, to an arrow shaft composed of anon-elastic fiber and a low elastic fiber, and a method formanufacturing the same.

[0003] 2. Background of the Related Art

[0004] Generally, a conventional archery arrow comprises, as shown inFIG. 3, a hollow arrow shaft, an arrow head fitted into a front end ofthe arrow shaft, a number of vanes attached to an outer periphery of arear end of the arrow shaft, and a notch fitted into the rear end, thearrow shaft being a major part among the above components.

[0005] Several methods and materials for manufacturing the arrow shafthave been proposed. A typical example of arrow shaft manufacturingmethods comprises the steps of: cutting; layering and winding; tapping;heat treating and cooling; releasing; and polishing.

[0006] The above method for manufacturing the arrow shaft includesseveral disadvantages as follows:

[0007] 1) To put a constant spin on the arrow, after carbon or glassfiber is layered and formed on a mandrel, and then the arrow shaft isground to have a wanted diameter and spin. However the arrow shaft isaccurately ground, a grinding error may be happened. Furthermore, at thefirst stage of grinding the material, the damage of the material is afactor of reducing the strength of the arrow shaft. There is anotherdrawback of deteriorating the arrow shaft in that the partial wear ishappened on the arrow shaft, and thus the linearity of the arrow shaftis lost.

[0008] 2) Since a polishing process is performed after previouslyaligning the linearity of the arrow shaft prior to polishing the arrowshaft, the linearity of the arrow shaft is lost, thereby increasing thepercent defective of the arrow shaft.

[0009] 3) Since the material (i.e., carbon fiber or glass fiber) islayered at larger amount than that of the spin in view of the grindingamount, the cost of the article is increased. In addition, there isanother drawback that since the surface of the arrow shaft is damaged,it is impossible to use the arrow shaft during a long time.

[0010] 4) After the spin and diameter of the arrow shaft are set, theweight of the arrow shaft is automatically determined due to theelasticity and specific gravity. Therefore, it is impossible to changethe weight of the arrow shaft. In particular, after the grindingprocess, it is impossible to set the weight of the arrow shaft to adesired weight depending upon the specification.

[0011] 5) According to the typical method, the strength of the arrowshaft is necessarily reduced due to the grinding of the arrow shaft. Inaddition, since the arrow shaft is painted or transferred or is designedby attaching a sticker on the peripheral surface in order to camouflagethe arrow shaft, an unnecessary process has to added, thereby causingreduced productivity and increased cost.

[0012] 6) If the transferring process is carried out, recessed portionsare happened on the surface of the arrow shaft due to the variations oftransferred thickness. During a long-range usage, the recessed portionswill be easily worn, and the transferred portions will be easilydetached from the surface of the arrow shaft.

[0013] 7) If the arrow shaft manufactured by the typical method isdamaged, a sharpen portion will be exposed since the material has amono-directional elasticity. Such a sharpen portion may can inflict afatal injury to a human body.

SUMMARY OF THE INVENTION

[0014] Accordingly, the present invention is directed to a method ofmanufacturing an arrow shaft that substantially obviates one or moreproblems due to limitations and disadvantages of the related art.

[0015] An object of the present invention is to provide an arrow shaftand a method for manufacturing the same, wherein a proper amount of anelastic sheet such as carbon or glass fiber proper that determines aspin of the arrow shaft is calculated to obtain a proper spin, and aproper amount of the elastic sheet is layered on a mandrel; and anon-elastic fiber or a low elastic fiber that has no effect on the spinis layered on a top of the elastic sheet.

[0016] Other object of the present invention is to provide an arrowshaft and a method for manufacturing the same, wherein a non-elasticfiber is ground to maintain the initial linearity of the arrow shaft.

[0017] Another object of the present invention is to provide an arrowshaft and a method for manufacturing the same, wherein a spin of thearrow shaft can be constantly maintained.

[0018] Still another object of the present invention is to provide anarrow shaft and a method for manufacturing the same, wherein the weightof the arrow shaft can be adjusted by controlling the grinding amount ofa non-elastic fiber or a low elastic fiber.

[0019] Further still another object of the present invention is toprovide an arrow shaft and a method for manufacturing the same, whereina desired design is printed on a surface of the arrow shaft using aprinting and transferring method.

[0020] Additional advantages, objects, and features of the inventionwill be set forth in part in the description which follows and in partwill become apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

[0021] To achieve the object and other advantages and in accordance withthe purpose of the invention, as embodied and broadly described herein,there is provided a method of manufacturing an arrow shaft by layeringand winding an elastic sheet around a peripheral surface of a mandrel,the method comprising the steps of: when the elastic sheet is layered onthe peripheral surface of the mandrel, layering a non-elastic sheet onan outermost surface of the elastic sheet; and winding the elastic sheetaround the mandrel together with the non-elastic sheet.

[0022] According to another aspect of the present invention, there isprovided an arrow shaft made of an elastic sheet such as carbon or glassfiber, the arrow shaft comprising: a non-elastic sheet adhered on anperipheral surface of the elastic sheet.

[0023] The non-elastic sheet comprises a natural fiber or cotton, and achemical fiber.

[0024] It is to be understood that both the foregoing generaldescription and the following detailed description of the presentinvention are exemplary and explanatory and are intended to providefurther explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this application, illustrate embodiment(s) of theinvention and together with the description serve to explain theprinciple of the invention. In the drawings:

[0026]FIG. 1 is a schematic view illustrating a process of manufacturingan arrow shaft according to one preferred embodiment of the presentinvention, in which sheets are adhered onto an external circumference ofa mandrel.

[0027]FIG. 2 is a cross sectional view illustrating an arrow shaftmanufactured by the method of the present invention.

[0028]FIG. 3 is a perspective view illustrating the construction of atypical archery arrow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Reference will now be made in detail to the preferred embodimentof the present invention, an example of which is illustrated in theaccompanying drawings.

[0030] The method for manufacturing an arrow shaft according to thepresent invention comprises the steps of spreading an elastic sheet suchas pre-impregnated or prepreged carbon or glass fiber, adhering anon-elastic or low elastic fiber, preferably a pre-impregnated orprepreged natural, synthetic, or glass fiber onto the elastic sheet,winding them onto a mandrel, and carrying out tapping, heattreating/cooling, releasing, and polishing processes.

[0031]FIG. 1 shows a process of winding the sheets onto the mandrel, theprocess being a major process of the present invention. Referring toFIG. 1, according to the method of the present invention, after a firstelastic sheet 102, a second elastic sheet 104, and a non-elastic fibersheet 106 are cut to have a desired length, respectively, the sheets areprepregs or pre-impregnated and then are wound onto a surface of themandrel 100.

[0032] The first elastic sheet 102 and second elastic sheet 104 are madeof elastic material. Preferably, the first and second elastic sheets aremade of a sheet made of carbon or glass fiber. One sheet made of carbonor glass fiber may be used, or a sheet of which the carbon fiber sheetand the glass fiber sheet are layered may be used. The non-elastic fibersheet 106 is referred to a fibroid material, in particular, a naturalfiber or cotton, or a chemical fiber. The non-elastic fiber may be ispainted or transferred with various designs to be under the disguise ofthe arrow shaft.

[0033] The arrow shaft 200 prepared by the above winding processincludes, as shown in FIG. 2, the first elastic sheet 102 formed in acylindrical shape, and the second elastic sheet 104 adhered onto theexternal circumference of the first elastic sheet 102. The non-elasticfiber sheet 106, preferably a painted fiber, is adhered onto theexternal circumference of the second elastic 104. The arrow shaft 200constructed as described above can address the drawbacks contained inthe typical arrow shaft. In particular, the present invention hasadvantages of controlling the weight of the arrow shaft and constantlymaintaining the initial linearity thereof.

[0034] One preferred embodiment of the present invention will now beexplained, but the present invention is not limited to the embodiment.

[0035] Embodiment

[0036] After a releasing agent is applied on the entire surface of anexternal circumference of a mandrel in order to easily carry out areleasing process (i.e., a process of releasing an article from themandrel), an adhesive is applied on the releasing agent. A carbon sheet,a glass fiber sheet, and a natural fiber sheet with various designsprinted are cut to have a desired length, respectively. At that time,the carbon sheet, the glass fiber sheet, and the natural fiber sheet arepre-impregnated (prepregs).

[0037] Next, as shown in FIG. 1, the glass fiber sheet is adhered on thecarbon sheet, and then the natural fiber sheet is adhered on the glassfiber. After an end of the carbon sheet is adhered on the surface of themandrel, the sheets are wound around the mandrel by a rolling unit (notshown), this process being hereinafter referred to a rolling process.

[0038] A film is wound around the entire surface of the resultantexecuted by the rolling process, preferably the natural fiber sheet,using a tapping unit (not shown), this process being hereinafterreferred to a tapping process. Preferably, polyethylene telephthalateresin (PET) film or oriented polypropylene(OPP) film is used as theabove film. The tapping process is executed immediately prior to theshape of the article executed by the rolling process, so that airexisted between each sheet layer may be discharged outwardly and aninterior layering degree of the article may be increased.

[0039] And then, the mandrel is heated with gradually varying atemperature during 4 hours, preferably under a temperature of 80 to 150°C. during 1 to 4 hours, thereby shaping sheet layers wound around themandrel. After that, the shaped article is released from the mandrel.

[0040] Finally, after both ends of the article released from the mandrelis cut to have a length of approximately 825 mm, the film is releasedfrom the surface of the natural fiber sheet. The method of manufacturingthe arrow shaft is completed by carrying out centerless polishing on thesurface of the natural fiber sheet.

[0041] The method of manufacturing the arrow shaft according to thepreferred embodiment of the present invention has some advantages asfollows:

[0042] A proper amount of the elastic material that determines the spinof the arrow shaft is previously calculated to obtain a proper spin, anda non-elastic fiber that has no effect on the spin is layered on a topof the elastic material, so that the arrow shaft having no spinvariations can be provided.

[0043] Since the non-elastic material is ground, the weight of the arrowshaft can be adjusted according to the grinding amount. In addition, thesurface of the arrow shaft is smoothed, and thus the arrow shaft is softto the touch. In particular, since the eccentricity and the initiallinearity of the arrow shaft can be maintained.

[0044] The present invention can camouflage the arrow shaft by paintingthe non-elastic fiber to have various designs. It can address drawbackscontained in the typical method that due to the transferring process theproductivity is decreased and the cost is increased.

[0045] If the arrow shaft manufactured by the present invention isdamaged, since the fiber encloses the damaged portion, a sharpen portionis not exposed, thereby protecting a human body.

[0046] The present invention grinds not an expensive elastic material,but an inexpensive non-elastic fiber, thereby reducing the cost of thearrow shaft and improving the productivity thereof.

[0047] The forgoing embodiment is merely exemplary and is not to beconstrued as limiting the present invention. The present teachings canbe readily applied to other types of apparatuses. The description of thepresent invention is intended to be illustrative, and not to limit thescope of the claims. Many alternatives, modifications, and variationswill be apparent to those skilled in the art.

What is claimed is:
 1. A method of manufacturing an arrow shaft bylayering and winding an elastic sheet around a peripheral surface of amandrel, the method comprising the steps of: when the elastic sheet islayered on the peripheral surface of the mandrel, layering a non-elasticsheet on an outermost surface of the elastic sheet; and winding theelastic sheet around the mandrel together with the non-elastic sheet. 2.The method as claimed in claim 1, wherein the non-elastic sheet is asheet made of a fibroid material
 3. The method as claimed in claim 2,wherein the non-elastic sheet comprises a natural fiber, cotton, and achemical fiber.
 4. The method as claimed in claim 1, wherein thenon-elastic sheet is painted to have various designs.
 5. An arrow shaftmanufactured by a method as claimed in claim
 1. 6. An arrow shaft madeof an elastic sheet such as carbon or glass fiber, the arrow shaftcomprising: a non-elastic sheet adhered on an peripheral surface of theelastic sheet.
 7. The arrow shaft as claimed in claim 6, wherein thenon-elastic sheet comprises a natural fiber, cotton, and a chemicalfiber.